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G. W. VVEITIVIAN` VARIABLE PRESSURE. HYDRAULIC PRESS Filed May- 4,. m22

GER/MANN W. WEITMAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO ECONOMY FUSE @t iMANUFACTURING CO., OF CHICAGO, ILLINOIS, A CORPORATION OIF NEW YORK.

VARIABLE-PRESSURE HYDRAULIC PRESS.

Application led May 4, 1922. Serial No. 558,485.

To all who/m I? may concern:

Be it known that I, GERMANN W. WEIT- MAN, a citizen yof the `UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inVariablePressure Hydraulic Presses, of which the folilowing is aspecification.

rIhe present invention relates to variable pressure hydraulic presses.

' In many classes of Work upon Which a press is used, excessivepressures may have a ruinous effect upon said Work. Various attemptshave been made heretofore to modify the effective pressure of ahydraulic In service, the tremendous pressures to` which the plunger issubjected sometimes cause the plunger to run askevv, and the presentinvention has for one of its objects the provision of means for reducingthe netl effective pressure of a hydraulic press, which means will alsobe effective in minimizing the skevving effect referred to.

A further object of the present invention is the provision of ahydraulic press in which the effective pressure may be convenientlychanged to suit varying operating conditions.

A further object is to provide a variable pressure hydraulic press inwhich the effective net pressure may be changed Without modifying thepressure per unit area of the operating fluid.

A further object is to provide a hydraulic press having means forvarying the effective net pressure thereof, Which means willcorrespondingly vary the amount of liquid which need be pumped into theoperating cylinder, whereby a reduction in the net effective pressure ofthe hydraulic press will involve a proportional reduction in the amountof pouver consumed.

A further object is to provide a variable pressure hydraulic press whichWill minimize theshocks incident to a system involving said press andWhich Will bc economical* which may be mounted upon the four standards11-11, being securely held thereon by means of the nuts 12-12. Said headmember lO has the cylinder portion 13, Which may be cored out for thereception of fluid T.

under pressure. Said head member is provided With a cylindrical hole 14`communieating With the interior of cylinder 15, which hole receives theplunger 15, adapted to have a running lit therein, A` packing gland 16may be-provided, fastened to the head member 10' by means of bolts17-17, which packing gland will hold packing 18 securely in place toprevent the escape of* fluid between plunger 15 and head member 10. l

The lovver'end of plunger 15 may be provided With a guide bar 19, whichmay have bearing engagement with the standardsif, 11%11, and which maycarry a die 20 for operation upon the material to be pressed. Thecylinder 13 may be provided with a connection 21 for fluid underpressure. Valve mechanism, which need not be described herein, isprovided for admitting i fluid under pressure to the cylinder 13 throughthe connection 21 and for allowing the fluid to escape through saidconnection 21 when the plunger is to be moved back to the beginning ofits operating stroke. Any preferred means may be provided for returningthe plunger after it has performed its operating stroke.

At the end of the plunger 15, opposite to the guide bar 19, is a tailram or extension bar 22 which may have a screw-threaded end 23 adaptedto be mounted in a corresponding screw-threaded recess in the end ofplunger 15. Said extension bar 22 when mounted in place in plunger 15should be rigid.v Said'. 'extension bar 22, plunger 15 and guide bar 19`should operate as onerigid member.' Said extension bar 22 extendsthrough the upper wall of cylinder `13, a packing gland 24E beinglprovided for preventing the escape of fluid along saidv eX- vtensionbar 22, said packing gland. 24E having a screw-threaded portionadaptedtobe mounted in the upperwall of f cylinder 13 and having apackingflange25 bolted' thereto for holding a packing member 26 in close engagement,with the extension lbar 22.

According-to the present invention-,the eX- Y tension bars -22 of'different cross sectional ldimensions maybe provided for the purposeofivarying the effective area of plunger 15.

TworfsiZes of extension bars are shown in Figures 2 and 3. y A4 setofextension bars 22 may bek provided, ,whiclliubars may havescrew-threaded end portions 23 of uniform vsize whereb said extensionbars 22 ma be interchangeably mounted in' the plunger 15.

v videdtocorrespond to the various extension y Different packing glands24 `will be probars 22,*all of said packing glands being-designed to beinterchangeably mounted in the top wall of cylinder 13;

The presentV invention presents the advantage that when the effectivepressure of the' hydraulic press is reduced, the amount of iiuid whichneed be pumped into the operating cylinder 13 is correspondinglyreduced.

7 Inasmuch as the Areduction in thel amount of fluid pumped involves `acorresponding reduction inthe power consumed, '1t will be realized that,with the tremendous pressures involved, the saving is very considerable.

The saving inpower is accompanied by the saving involved in the shocksupon the mavichineryv. In aplant using a number ofhyl 'f draulicvApresses of 1 the -kind referred to,

lwherein a `number of presses are operated from a 'centralpumpingpoint,` a reduction 1n isol capacity of the presses is accompanied by anincrease -in the'number of presses which can Arbeoperated inasmuch asless uid need be pumpedto each press. The reduction in the totalpressure to the value suitable forthe ywork in the press iscorrespondingly easier on dies.

Inasmuchas provides an addedv bearingfforthe reciprocating parts of thepress, which bearing is distant from the guide bar 19, there is a greatreduction in the tendency for the plunger to run askew. Then it isconsidered that any skewing effect ofthe plunger involves-the danger ofscoring'the lbearing ent to cover all such modifications that fallwithin the scope of the invention as defined by the appended claims.-

I claim: .i l n 1. A hydraulic press having-a head portion provided witha fluid receiving 4chamber, a plunger slidably mounted in said headmember, a plurality of extension bars of varying cross sectionaldimensions interchangeably applicable to said plunger for reducing theeffective area thereof, and a plurality of packing glandsinterchangeably applicable to said enclosing means for packing saidextension bars.

2. A hydraulic press comprising a reciprocating plunger,.enclosing meanstherefor including a pressure cylinder, guide members,

said plunger having a guide bar rigid therewith operatively associatedwith said guide members, a plurality` of extension bars of varying crosssectional dimensions interchangeably applicable to said plunUer to forma rigid connection therewith for reducing the effective area of saidplunger, and a plurality ofl packing glands interchangeably applicableto said enclosing means for packing Said extension bars.

Signed at Chicago, I1linois,this 22nd day of April, 1922. the engagementbetween they extension bar` 22 andthe packing gland 24 ennMANN w.WEITMAN.

